The present invention relates to processes for manufacturing detersive surfactants, especially those containing branched-chain hydrophobic units.
Conventional detersive surfactants comprise molecules having a water-solubilizing substituent (hydrophilic group) and an oleophilic substituent (hydrophobic group). Such surfactants typically comprise hydrophilic groups such as carboxylate, sulfate, sulfonate, amine oxide, polyoxyethylene, and the like, attached to an alkyl, alkenyl or alkaryl hydrophobe usually containing from about 10 to about 20 carbon atoms. Accordingly, the manufacturer of such surfactants must have access to a source of hydrophobe groups to which the desired hydrophile can be attached by chemical means. The earliest source of hydrophobe groups comprised the natural fats and oils, which were converted into soaps (i.e., carboxylate hydrophile) by saponification with base. Coconut oil and palm oil are still used to manufacture soap, as well as to manufacture the alkyl sulfate (xe2x80x9cASxe2x80x9d) class of surfactants. Other hydrophobes are available from petrochemicals, including alkylated benzene which is used to manufacture alkyl benzene sulfonate surfactants (xe2x80x9cLASxe2x80x9d).
The literature asserts that certain branched hydrophobes can be used to advantage in the manufacture of alkyl sulfate detersive surfactants; see, for example, U.S. Pat. No. 3,480,556 to deWitt, et al., Nov. 25, 1969. However, it has been determined that the beta-branched surfactants described in the ""556 patent are inferior with respect to certain solubility parameters, as evidenced by their Krafft temperatures. It has further been determined that surfactants having branching towards the center of carbon chain of the hydrophobe have much lower Krafft temperatures. See: xe2x80x9cThe Aqueous Phase Behavior of Surfactantsxe2x80x9d, R. G. Laughlin, Academic Press, N.Y. (1994) p. 347. Accordingly, it has now been determined that such surfactants are preferred for use especially under cool or cold water washing conditions (e.g., 20xc2x0 C.-5xc2x0 C.).
One problem associated with the manufacture of detersive surfactants having hydrophobe groups with mid- or near-mid chain branching is the lack of a ready source of such hydrophobes. By the present invention, a process is described for manufacturing such branched hydrophobes and converting them into mid- or near-mid chain branched surfactants.
The present invention encompasses a process for preparing mid- to near mid-chain branched olefins (primarily, methyl branched at or near the mid-chain region). Such materials are then used as the basic feedstock which provides the hydrophobic portion of branched-chain detersive surfactants.
The process herein is illustrated by the following reaction sequence.
1) Alpha-Olefin Dimerization 
wherein R and Rxe2x80x2 may be the same or different linear alkyl, and wherein R is C3-C7, preferably C5 to C7 linear alkyl, and Rxe2x80x2 is C3-C7, preferably C5-C7 linear alkyl. For use in preparing surfactants in cleaning products such as laundry detergents, dishwashing liquids, and the like, R and Rxe2x80x2 are preferably the same or within one or two carbon atoms of each other in chain length. Some linear olefins may also result from the dimerization and these can optionally be removed using molecular sieves. Step 1 of the process herein is designed to provide branched olefins which preferably contain from about 12 to about 18 (avg.) total carbon atoms.
2) Alcohol Production
In Step 2 (Route A), the olefin mixture for Step 1 can be pre-randomized to enhance the ultimate formation of alcohols (i) and (ii) in subsequent Step 3. Alternatively (Step 2, Route B), this pre-randomization step can be deleted and the Oxo catalyst, itself, can randomize the final product among the three possible terminal positions. 
The Oxo process to make alcohols is described in detail in Kirk-Othmer Encyclopedia of Chemical Technology, 4th Edition, Volume 1, pp. 903-8 (1991), Jacqueline 1. Kroschwitz, Executive Editor, Wiley-Interscience, N.Y. The catalyst for this step is, for example, cobalt-carbon monoxide-organophosphine.
The alcohol mixture of Step (2) of the present process comprises branched-chain primary alcohol compounds of the following formulae for use in Step (3), below. 
It is to be understood that when CH2OH is substituted on R or Rxe2x80x2 it is primarily on their respective terminal carbons or to a lesser extent on their penultimate carbons. Desirably, minimal amounts of compounds of the formula (iii) are present in Step (3).
3) Surfactant Production 
Advantageously, the present process results in no geminal branching; i.e., no xe2x80x9cquaternaryxe2x80x9d carbon substitution. Steric hindrance will block inverse addition to vinylidene carbon with cobalt-carbon monoxide-organophosphine which otherwise would form a non-biodegradable quaternary carbon. Moreover, little (less than about 3%) vicinal branching occurs. Of course, some of the overall feedstock may remain unbranched. Typically, and preferably from the standpoint of cleaning performance and biodegradability, the present process provides hydrophobes with one near-central methyl in the case of isomers i) and ii).
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All documents cited herein are, in relevant part, incorporated herein by reference.
1) Olefin Dimerization:
The present invention encompasses, in a process for preparing surfactant precursor hydrophobes from dimerization of two same or near same chain length alpha-olefins to form a detergent range vinylidene olefin. These alpha olefins C5 to C10, preferably C7 to C9 are dimerized to give C10 to C20, preferably C14 to C18 vinylidene olefins which upon Oxo reaction give C11 to C21, preferably C15 to C19 alcohols. There are a number of processes for accomplishing said dimerization; see U.S. application Ser. No. 9,200,398, U.S. Pat. No. 4,658,078, U.S. Pat. No. 4,973,788; O. S. Vostrikova, A. G. Ibragimov, G. A. Tolstikov, L. M. Zelenova and U. M. Dzhemilev, Izv. Akad. Nauk SSSR, Ser. Khim. (1980), (10), 2330-2 [Chem. Abstr. 94:65032]; Jpn. Kokai Tokkyo Koho, 06228016 A2 [Chem. Abstr. 122:186930].
2) Alcohol Production
Route A
part a) The carbon-carbon double bond of the vinylidene olefin is pre-isomerized using a method such as Shell uses to isomerize alpha-olefins in their SHOP process; see Kirk-Othmer Encyclopedia of Chemical Technology, 4th Edition, Volume 17, pp. 848-50 (1996), Jacqueline I. Kroschwitz, Executive Editor, Wiley-Interscience, N. Y. and Chemical Economics Handbook, pp. 681.5030K-L, Stanford Research Institute, Menlo Park, Calif. 94025, October 1993.
part b) Oxo chemistry is used to convert the pre-isomerized vinylidene olefin (now largely internal olefin) to a primary alcohol mixture. For this an Oxo catalyst which isomerizes the double bond to alpha positions prior to carbonylation is desired as is the case using cobalt-carbonyl-phosphine catalysts in the one step process, see Kirk-Othmer Encyclopedia of Chemical Technology, 4th Edition, Volume 1, pp. 903-8 (1991). Route A, (that is including pre-isomerization) is undertaken to assure relatively high yields of alcohols i and ii versus alcohol iii. Note alcohol sulfates of i and ii are desired surfactants whereas that of iii may be deficient.
Route B
This step utilizes the same Oxo catalyst on the vinylidene olefin directly without its pre-isomerization. This relies upon the catalyst to completely isomerize the carbonxe2x80x94carbon double bond of the vinylidene olefin prior to carbonylation. The object is to obtain as much i and ii relative to iii as is obtained in Route A.
Other fatty alcohol-derived surfactants can also be made, e.g., alkyl ethoxyl sulfates (AES), alkyl polyglucosides (APG), etc. Note that surfactants other than alcohol sulfates or AES may be made by oxidizing said alcohol or its aldehyde intermediate into a carboxylate (i.e., a branched-chain soap). This soap can be an excellent surfactant and/or detergent builder in and of itself. This carboxylate can also be used as a feedstock and converted to branched acyl-taurates, -isethionates, -sarcosinates, -N-methylglucamide or other acyl-derived surfactants using art-disclosed techniques.
Branched-chain surfactants of the type resulting from the present process can be used in all manner of cleaning compositions. Such compositions include, but are not limited to: granular, bar-form and liquid laundry detergents; liquid hand dishwashing compositions; liquid, gel and bar-form personal cleansing products; shampoos; dentifrices; hard surface cleaners, and the like. Such compositions can contain a variety of conventional detersive ingredients. The following listing of such ingredients is for the convenience of the formulator, and not by way of limitation of the types of ingredients which can be used with the branched-chain surfactants herein.
The branched-chain surfactants herein can be used in combination with detergency builders. Such builders include, for example, 1-10 micrometer zeolite A, polycarboxylate builders such as citrate, layered silicate builders such as xe2x80x9cSKS-6xe2x80x9d (Hoechst) and phosphate materials, especially sodium tripolyphosphate (xe2x80x9cSTPPxe2x80x9d). Most laundry detergents typically comprise at least about 1% builder, more typically from about 5% to about 80% builder or mixtures of builders.
Enzymes, such as proteases, amylases, lipases, cellulases, peroxidases, and mixtures thereof, can be employed in detergent compositions containing the branched-chain surfactants. Typical detergent compositions comprise from about 0.001% to about 5% of commercial enzymes.
Detergent compositions can also contain polymeric soil release agents (SRA""s). Such materials include, for example, anionic, cationic and non-charged monomer units, especially polyester materials. Preferred materials of this type include oligomeric terephthalate esters, sulfonated substantially linear ester oligomers comprising a backbone of terephthaloyl and oxyalkyleneoxy-repeat units and phthalolyl-derived sulfonated terminal moieties. A variety of SRA""s are described, for example, in U.S. Pat. Nos. 4,968,451; 4,711,730; 4,721,580; 4,702,857; 4,877,896; 5,415,807; and in other literature references. Such soil release materials typically comprise from about 0.01% to about 10% of finished detergent compositions.
Detergent compositions may also optionally contain bleaching compositions comprising a bleaching agent and one or more bleach activators. If present, bleaching agents such as percarbonate or perborate (especially perborate monohydrate xe2x80x9cPBIxe2x80x9d) typically are used at levels from about 1% to about 30% of finished detergent compositions. Bleach activators such as nonanoyloxy-benzene sulfonate (xe2x80x9cNOBSxe2x80x9d) and tetraacetyl ethylenediamine (xe2x80x9cTAEDxe2x80x9d), and mixtures thereof, can be used to enhance the bleaching activity of materials such as perborate and percarbonate. If present, the amount of bleach activator will typically be from about 0.1% to about 60% of a bleaching composition comprising a bleaching agentplus-bleach activator. Other bleaching agents such as the so-called xe2x80x9cphotoactivatedxe2x80x9d bleaches (see U.S. Pat. No. 4,033,718) can also be used. Sulfonated zinc phthalocyanine is an especially preferred photoactivated bleaching agent.
Detergent compositions can also contain clay soil removal/antiredeposition agents such as ethoxylated tetraethylene pentamine; see U.S. Pat. No. 4,597,898. Such materials typically comprise from about 0.01% to about 10% of fully-formulated laundry detergents.
Detergent compositions can also contain from about 0.1% to about 7% of polymeric dispersing agents, which are especially useful in the presence of zeolite and/or layered silicate builders. Such materials are known in the art (see U.S. Pat. No. 3,308,067). Such materials include acrylatelmalic-based copolymers, such as described in EP 193,360, as well as polyethylene glycol (xe2x80x9cPEGxe2x80x9d).
Detergent compositions herein can also include various brighteners, dye transfer inhibiting agents (especially polymers of N-vinylpyrrolidone and N-vinylimidazole), suds suppressors (especially silicones), chelating agents such as nitrilotriacetate, ethylenediamine disuccinate, and the like. Such materials will typically comprise from about 0.5% to about 10%, by weight, of fully-formulated cleaning compositions.
Moreover, it is to be understood that the branched-chain surfactants prepared in the manner of the present invention may be used singly in cleaning compositions or in combination with other detersive surfactants. Typically, fully-formulated cleaning compositions will contain a mixture of surfactant types in order to obtain broad-scale cleaning performance over a variety of soils and stains and under a variety of usage conditions. One advantage of the branched-chain surfactants herein is their ability to be readily formulated in combination with other known surfactant types. Nonlimiting examples of additional surfactants which may be used herein typically at levels from about 1% to about 55%, by weight, include the unsaturated sulfates such as oleyl sulfate, the C10-C18 alkyl alkoxy sulfates (xe2x80x9cAEXSxe2x80x9d; especially EO 1-7 ethoxy sulfates), C10-C18 alkyl alkoxy carboxylates (especially the EO 1-5 ethoxycarboxylates), the C10-18 glycerol ethers, the C10-C18 alkyl polyglycosides and their corresponding sulfated polyglycosides, and C12-C18 alpha-sulfonated fatty acid esters. Nonionic surfactants such as the ethoxylated C10-C18 alcohols and alkyl phenols, (e.g., C10-C18 EO (1-10) can also be used. If desired, other conventional surfactants such as the C12-C18 betaines and sulfobetaines (xe2x80x9csultainesxe2x80x9d), C10-C18 amine oxides, and the like, can also be included in the overall compositions. The C10-C18 N-alkyl polyhydroxy fatty acid amides can also be used. Typical examples include the C12-C18 N-methylglucamides. See WO 9,206,154. Other sugar-derived surfactants include the N-alkoxy polyhydroxy fatty acid amides, such as C10-C18 N-(3-methoxypropyl) glucamide. The N-propyl through N-hexyl C12-C18 glucamides can be used for low sudsing. C10-C20 conventional soaps may also be used. If high sudsing is desired, the branched-chain C10-C16 soaps may be used. C10C14 alkyl benzene sulfonates (LAS), which are often used in laundry detergent compositions, can also be used with the branched surfactants herein.